1. Field of the Invention
The present invention relates to a new process for the production of water- and solvent-resistant coated substrates by coating substrates with solutions or dispersions of particular anionically-modified polyisocyanate addition products in an aqueous solvent or dispersant and subsequently thermally treating the resulting coating. The present invention also relates to the aqueous solutions or dispersions of anionically-modified polyisocyanate addition products.
2. Description of the Prior Art
Aqueous solutions or dispersions of anionically-modified polyisocyanate addition products, particularly aqueous dispersions of anionically-modified polyurethanes or polyurethane-polyureas and the use thereof for the production of coatings are already known (c.f., for example, DE-PS No. 1,184,946, DE-PS No. 1,178,586, DE-AS No. 1,237,306, DE-OS No. 1,495,745, DE-OS No. 1,595,602, DE-OS No. 1,770,068, DE-OS No. 2,019,324, DE-OS No. 2,314,512 or D. Dieterich et al., Angew. Chem. 82, 53 (1970)).
The dispersibility of the polyisocyanatepolyaddition products contained in these dispersions is based on the presence of incorporated ionic centers, particularly incorporated sulphonate or carboxylate groups. In the production of coated substrates from these dispersions, the ionic centers generally remain in the resulting coated substrates, thereby reducing the water resistance of the resulting coating.
Thus, an object of the present invention is to provide a new process for the production of coated substrates using aqueous solutions or dispersions of anionically-modified polyisocyanate addition products which does not suffer from this serious disadvantage.
This function can be achieved by the process according to the invention which is described in more detail in the following.